For Gwyneth Paltrow, one red-carpet premiere, two parties and three wardrobe changes is all in a day’s work. Particularly in Cannes. Fortunately, the preview of her short for Tod’s dovetailed nicely with the premiere of her in-competition feature “Two Lovers.” “I can’t believe how well that worked out,” Paltrow said, perched on a deck chair aboard Altair, Diego Della Valle’s yacht, on Monday afternoon.

At the suggestion of Mario Testino, Tod’s chose Paltrow to be in both its Dennis Hopper-directed film and the next ad campaign. The Oscar winner spent four days in Italy last week filming the five-minute promotional short, Hopper’s self-described nod to Fellini. Paltrow plays a movie star who gets spooked mid-interview by paparazzi, thus fleeing the restaurant and leaving behind her Tod’s Pashmy bag. A young male reporter must push through the throng at her premiere to reunite her with it.

Paltrow’s other project, “Two Lovers,” has a much longer backstory. “[Director] James Gray and I had talked about working together, but it never quite worked out,” she recalls. “Then he called me one day and said, ‘I wrote a movie for you.’ I said, ‘Wow, OK. I hope I like it.’ I loved it.”

As a Long Island woman entangled in an affair with a married man, Paltrow befriends Joaquin Phoenix’s character, who has come home to live with his parents. “They form this amazing relationship that’s like a love story, but it’s not,” she says cryptically. Paltrow calls the movie “the opposite of ‘Iron Man'” because “it’s just acting. There’s no blowups or explosives. It’s very small and personal.”

As for the festival, she’s making a quick 36-hour tour of it — sans her kids, Apple, 4, and Moses, 2. “It would have been nice if they were here, but it’s too much to schlep them and take them out of their routine,” she explains. Besides, Paltrow barely had time to dress for the yacht party (Lanvin), the Chopard Trophee party (another Lanvin) and the “Two Lovers” premiere (Chanel). “I had a dress disaster. They altered one of them too small,” she sighs. Hopefully, that’s the only mishap she faces. “Maybe I should stop drinking alcohol,” she considers, Champagne in hand, shortly before her first trip up the Palais. “I hear there are a lot of stairs.”